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Copper alloys; Dislocations (crystals); Energy barriers; Road construction; Strain rate, High temperature; High temperature behavior; Intermediate temperatures; Power law scalings; Predictive modeling; Solute strengthening; Solution strengthening; Zero temperatures, Temperature
Abstract:
The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier δE(τ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of δE(τ). The new model predicts that the wellestablished low-temperature, with energy barrier δEb and zero temperature flow stress τy0, transitions to a near-logarithmic form for stresses in the regime 0.2τ/τ y0 τ ≤ 0.5 and then transitions to a power-law form at even lower stresses τ/τ y0lt;0.03. δEb and τ y0 remains as the reference energy and stress scales over the entire range of stresses. The model is applied to literature data on solution strengthening in Cu alloys and captures the experimental results quantitatively and qualitatively. Most importantly, the model accurately captures the transition in strength from the low-temperature to intermediatetemperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility. © 2016 IOP Publishing Ltd.
